The present invention relates to methods and compositions for preventing or reducing cancers in humans or animals. More particularly, the present invention relates to immunogenic compositions comprising growth factors, active fragments thereof, antibodies specific for growth factors, and methods of use thereof.
While many cancers are treatable by chemotherapeutic agents, a significant number of cancers are intrinsically drug resistant and others acquire resistance during or following chemotherapy. Cancers frequently are resistant to more than one type of drug. This phenomenon is called multidrug resistance or MDR. Consequently, there is a great need for compositions and methods that can be used in addition to, or as alternatives to, chemotherapy for the treatment of cancer.
A major clinical problem of cancer is metastasis. By the time that the primary tumor is identified and localized, seed cells often have escaped and migrated or metastasized to other organs in the body where they establish secondary tumors. Surgical procedures are rarely sufficient to cure a cancer because even after the primary tumor is removed multiple secondary tumors survive and proliferate. Consequently, there exists an immediate and pressing need for techniques of eradicating secondary tumors that already exist.
Cancer cells that escape the primary tumor are usually carried in the venous and lymphatic circulation until they lodge in a downstream capillary bed or lymph node. However, only 1 in 10,000 of the cancer cells that escape the primary tumor survive to establish a secondary tumor. Successful cancer cells are those that find a favorable environment for survival and growth. The favorable environment include hormones and growth-promoting factors. Stimulating factors include local growth factors, hormones produced by the host, and autostimulating growth factors produced by the tumor cells themselves. Consequently, there is an immediate and pressing need for techniques capable of preventing or inhibiting metastasis of cancer and the formation of secondary tumors.
Additionally, many other hyperproliferative disorders exist. Hyperproliferative disorders are caused by non-cancerous (i.e. non-neoplastic) cells that overproduce in response to a particular growth factor. Examples of such hyperproliferative disorders include diabetic retinopathy, psoriasis, endometriosis, macular degenerative disorders and benign growth disorders such as prostate enlargement and lipomas.
It is known that many new cancers are initiated, and existing cancers and hyperproliferative disorders stimulated, by growth factors that affect either the cancer cell itself, or normal tissue around the cancer that facilitate survival of the cancer cell (i.e., angiogenesis factors). There is a direct correlation between the circulating level of certain growth factors and cancer proliferation. A potential method of treatment would be to regulate the level of circulating growth factors in a patient to prevent cancer initiation or recurrence, and to reduce or eliminate existing cancers. What is needed, therefore, are compositions that remove the target growth factors from circulation or inhibit the growth-promoting activity of growth factors.
Cellular proliferation is a normal ongoing process in all living organisms and is one that involves numerous factors and signals that are delicately balanced to maintain regular cellular cycles. The general process of cell division is one that consists of two sequential processes: nuclear division (mitosis), and cytoplasmic division (cytokinesis). Because organisms are continually growing and replacing cells, cellular proliferation is a central process that is vital to the normal functioning of almost all biological processes. Whether or not mammalian cells will grow and divide is determined by a variety of feedback control mechanisms, which include the availability of space in which a cell can grow, and the secretion of specific stimulatory and inhibitory factors in the immediate environment.
When normal cellular proliferation is disturbed or somehow disrupted, the results can affect an array of biological functions. Disruption of proliferation could be due to a myriad of factors such as the absence or overabundance of various signaling chemicals, growth factors or presence of altered environments. Some disorders characterized by abnormal cellular proliferation include cancer, abnormal development of embryos, improper formation of the corpus luteum, difficulty in wound healing as well as malfunctioning of inflammatory and immune responses.
Cancer is characterized by abnormal cellular proliferation. Cancer cells exhibit a number of properties that make them dangerous to the host, often including an ability to invade other tissues and to induce capillary ingrowth, which assures that the proliferating cancer cells have an adequate supply of blood. One of the defining features of cancer cells is that they respond abnormally to control mechanisms that regulate the division of normal cells and continue to divide in a relatively uncontrolled fashion until they kill the host.
Angiogenesis and angiogenesis related diseases are closely affected by cellular proliferation and therefore cytokines and growth factors. As used herein, the term xe2x80x9cangiogenesisxe2x80x9d means the generation of new blood vessels into a tissue or organ. Under normal physiological conditions, humans or animals undergo angiogenesis only in very specific restricted situations. For example, angiogenesis is normally observed in wound healing, fetal and embryonal development and formation of the corpus luteum, endometrium and placenta. The term xe2x80x9cendotheliumxe2x80x9d is defined herein as a thin layer of flat cells that lines serous cavities, lymph vessels, and blood vessels. These cells are defined herein as xe2x80x9cendothelial cellsxe2x80x9d. The term xe2x80x9cendothelial inhibiting activityxe2x80x9d means the capability of a molecule to inhibit angiogenesis in general. The inhibition of endothelial cell proliferation also results in an inhibition of angiogenesis.
Both controlled and uncontrolled angiogenesis are thought to proceed in a similar manner. Endothelial cells and pericytes, surrounded by a basement membrane, form capillary blood vessels. Angiogenesis begins with the erosion of the basement membrane by enzymes released by endothelial cells and leukocytes. The endothelial cells, which line the lumen of blood vessels, then protrude through the basement membrane. Angiogenic stimulants induce the endothelial cells to migrate through the eroded basement membrane. The migrating cells form a xe2x80x9csproutxe2x80x9d off the parent blood vessel, where the endothelial cells undergo mitosis and proliferate. The endothelial sprouts merge with each other to form capillary loops, creating the new blood vessel.
Persistent, unregulated angiogenesis occurs in a multiplicity of disease states, tumor metastasis and abnormal growth by endothelial cells and supports the pathological damage seen in these conditions. The diverse pathological disease states in which unregulated angiogenesis is present have been grouped together as angiogenic-dependent, angiogenic-associated, or angiogenic-related diseases. These diseases are a result of abnormal or undesirable cell proliferation, particularly endothelial cell proliferation.
The hypothesis that tumor growth is angiogenesis-dependent was first proposed in 1971 by Judah Folkman (N. Engl. Jour. Med. 285:1182 1186, 1971). In its simplest terms the hypothesis proposes that expansion of tumor volume beyond a certain phase requires the induction of new capillary blood vessels. For example, pulmonary micrometastases in the early prevascular phase in mice would be undetectable except by high power microscopy on histological sections. Further indirect evidence supporting the concept that tumor growth is angiogenesis dependent is found in U.S. Pat. Nos. 5,639,725, 5,629,327, 5,792,845, 5,733,876, and 5,854,205, all of which are incorporated herein by reference.
One example of a disease mediated by angiogenesis is ocular neovascular disease. This disease is characterized by invasion of new blood vessels into the structures of the eye such as the retina or cornea. It is the most common cause of blindness and is involved in approximately twenty eye diseases. In age-related macular degeneration, the associated visual problems are caused by an ingrowth of chorioidal capillaries through defects in Bruch""s membrane with proliferation of fibrovascular tissue beneath the retinal pigment epithelium. Angiogenic damage is also associated with diabetic retinopathy, retinopathy of prematurity, corneal graft rejection, neovascular glaucoma and retrolental fibroplasia. Other diseases associated with corneal neovascularization include, but are not limited to, epidemic keratoconjunctivitis, Vitamin A deficiency, contact lens overwear, atopic keratitis, superior limbic keratitis, pterygium keratitis sicca, sjogrens, acne rosacea, phylectenulosis, syphilis, Mycobacteria infections, lipid degeneration, chemical burns, bacterial ulcers, fungal ulcers, Herpes simplex infections, Herpes zoster infections, protozoan infections, Kaposi sarcoma, Mooren ulcer, Terrien""s marginal degeneration, mariginal keratolysis, rheumatoid arthritis, systemic lupus, polyarteritis, trauma, Wegener""s sarcoidosis, Scleritis, Steven""s Johnson disease, periphigoid radial keratotomy, and corneal graph rejection.
Diseases associated with retinal/choroidal neovascularization include, but are not limited to, diabetic retinopathy, macular degeneration, sickle cell anemia, sarcoid, syphilis, pseudoxanthoma elasticum, Paget""s disease, vein occlusion, artery occlusion, carotid obstructive disease, chronic uveitis/vitritis, mycobacterial infections, Lyme""s disease, systemic lupus erythematosis, retinopathy of prematurity, Eales disease, Bechet""s disease, infections causing a retinitis or choroiditis, presumed ocular histoplasmosis, Best""s disease, myopia, optic pits, Stargart""s disease, pars planitis, chronic retinal detachment, hyperviscosity syndromes, toxoplasmosis, trauma and post-laser complications. Other diseases include, but are not limited to, diseases associated with rubeosis (neovascularization of the angle) and diseases caused by the abnormal proliferation of fibrovascular or fibrous tissue including all forms of proliferative vitreoretinopathy.
Another disease in which angiogenesis is believed to be involved is rheumatoid arthritis. The blood vessels in the synovial lining of the joints undergo angiogenesis. In addition to forming new vascular networks, the endothelial cells release factors and reactive oxygen species that lead to pannus growth and cartilage destruction. The factors involved in angiogenesis may actively contribute to, and help maintain, the chronically inflamed state of rheumatoid arthritis.
Factors associated with angiogenesis may also have a role in osteoarthritis. The activation of the chondrocytes by angiogenic-related factors contributes to the destruction of the joint. At a later stage, the angiogenic factors would promote new bone formation. Therapeutic intervention that prevents the bone destruction could halt the progress of the disease and provide relief for persons suffering with arthritis.
Chronic inflammation may also involve pathological angiogenesis. Such disease states as ulcerative colitis and Crohn""s disease show histological changes with the ingrowth of new blood vessels into the inflamed tissues. Bartonellosis, a bacterial infection found in South America, can result in a chronic stage that is characterized by proliferation of vascular endothelial cells. Another pathological role associated with angiogenesis is found in atherosclerosis. The plaques formed within the lumen of blood vessels have been shown to have angiogenic stimulatory activity.
One of the most frequent angiogenic diseases of childhood is the hemangioma. In most cases, the tumors are benign and regress without intervention. In more severe cases, the tumors progress to large cavernous and infiltrative forms and create clinical complications. Systemic forms of hemangiomas, the hemangiomatoses, have a high mortality rate. Therapy resistant hemangiomas exist that cannot be treated with therapeutics currently in use.
Angiogenesis is also responsible for damage found in hereditary diseases such as Osler-Weber-Rendu disease, or hereditary hemorrhagic telangiectasia. This is an inherited disease characterized by multiple small angiomas, tumors of blood or lymph vessels. The angiomas are found in the skin and mucous membranes, often accompanied by epistaxis (nosebleeds) or gastrointestinal bleeding and sometimes with pulmonary or hepatic arteriovenous fistula.
Thus it is clear that cellular proliferation, particularly endothelial cell proliferation, plays a major role in the metastasis of a cancer. If this abnormal or undesirable proliferation activity could be repressed, inhibited, or eliminated, then the tumor, although present, would not grow. In the disease state, prevention of abnormal or undesirable cellular proliferation and angiogenesis could avert the damage caused by the invasion of the new microvascular system. Therapies directed at control of the cellular proliferative processes could lead to the abrogation or mitigation of these diseases.
What are needed are compositions and methods which can inhibit abnormal or undesirable cellular proliferation related to tumors. The compositions should be able to overcome the activity of endogenous growth factors in premetastatic tumors and prevent the dissemination of cancerous cells thereby inhibiting the development of disease and the growth of tumors. The compositions should also be able to modulate the formation of capillaries in angiogenic processes, such as wound healing and reproduction. Finally, the compositions and methods for inhibiting cellular proliferation should preferably be non-toxic and produce few side effects.
The present invention generally comprises methods and compositions for preventing or treating cancers. More particularly, the present invention involves immunogenic growth factor-containing compositions comprising growth factors or active fragments thereof and delivery vehicles. Though not wishing to be bound by the following theory, the compositions of the present invention may elicit either a cellular or immune response that results in the prevention and reduction of cancer.
The present invention provides a method of vaccinating a human or animal against growth factors that are associated with specific cancer types and hyperproliferative disorders. Certain cancers are associated with only one growth factor whereas other cancers are regulated several by growth factors. For example, certain T cell lymphomas produce the growth factor IL-2, which stimulates proliferation by autocrine action; other tumors produce factors that promote angiogenesis and stimulate growth of metastatic cancer lesions by inducing vascularization of tissue at the site of metastases.
Examples of growth factor-containing compositions comprise delivery or carrier vehicles such as liposomes or vesicles having portions of growth factor, growth factor fragments, synthetic peptides of certain epitopes of growth factors, or modified growth factor fragments presented on their external surfaces. In an alternative embodiment a growth factor, or immunogenic fragment thereof, may be partially or totally encapsulated with a carrier such as a liposome. In another alternative embodiment of the present invention, the growth factors or active portions thereof may be transported to desired sites by delivery mechanisms comprising the use of colloidal metals such as colloidal gold. The above described compositions are useful as vaccines to induce immunity against growth factors which otherwise are recognized as xe2x80x9cselfxe2x80x9d by the immune system and are not naturally antigenic. The compositions are further useful in therapeutic regimens for reducing the proliferation of tumor cells. Though not wishing to be bound by the following theory, it is thought that the resulting circulating antibodies bind growth factor and thereby prevent the initiation of cancer proliferation, reduce existing cancer, or inhibit the spread of cancers.
The present invention also comprises isolated and recombinant antibodies specific for growth factors. Isolated antibodies are produced by, and purified from humans or animals with strong immune systems, and injected into humans or animals with weak or non-functional immune systems in need of such circulating antibodies. Thus, according to the present invention, cancers are reduced or inhibited either by active immunization of an individual using antigenic growth factor-containing compositions, or by passive immunization via administering an antibody or a group of antibodies specific for growth factor epitopes. Additionally, patients are immunized with the growth factor composition prior to the initiation or recurrence after treatment of cancer.
Accordingly, it is an object of the present invention to provide methods and compositions for reducing cancer and inhibiting tumor growth in a human or animal having cancer.
It is another object of the present invention to provide methods and compositions for treating and preventing the occurrence or spread of cancer.
It is a further object of the present invention to provide methods and compositions for reducing cancer and inhibiting tumor growth in a human or animal having cancer by eliciting an active cellular and humoral response in the host.
Another object of the present invention is to provide methods and compositions for reducing and preventing the occurrence of hyperproliferative disorders.
It is yet another object of the present invention to provide methods and compositions for vaccinating a human or animal against selected growth factors.
It is yet another object of the present invention to provide methods and compositions for passively immunizing a human or animal against selected growth factors.
Another object of the present invention is to provide growth factor-containing compositions that are antigenic and elicit an immune response against growth factor in humans or animals.
Another object of the present invention is to provide a vaccine composition comprising a growth factor that is non-immunogenic in a human or animal to be immunized with the composition; and a carrier wherein the growth factor is presented on the surface of the carrier such that the composition is immunogenic for the growth factor when administered into the human or animal.
It is yet another object of -the present invention to provide a growth factor containing composition wherein the growth factor comprises fibroblast (FGF), interleukins, kerotinocyte growth factor, colony stimulating factors, epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), transforming growth factors, Schwann cell-derived growth factor, nerve growth factor (NGF), platelet-derived growth factor (PDGF), insulin-like growth factors 1 and 2 (IGF-1 and IGF-2), glial growth factor, tumor necrosis factors, prolactin and growth hormone.
Yet another object of the present invention is to provide growth factor peptide fragments modified with antigenic moieties to increase an individual""s response to growth factor and methods of use thereof.
It is yet another object of the present invention to provide growth factor containing compositions wherein the carrier for the growth factor comprises a liposome.
It is another object of the present invention to provide growth factor containing compositions wherein the carrier for the growth factor comprises a colloidal metal.
Another object of the present invention is to provide growth factor containing compositions wherein the carrier is a baculovirus-derived vesicle.
It is yet another object of the present invention to provide growth factor peptide fragments and growth factor peptide fragments in liposomes.
It is still another object of the present invention to provide growth factor peptide fragment-containing compositions in combination with pharmaceutically acceptable adjuvants to stimulate the immune response.
It is yet another object of the present invention to provide compositions and methods for treating diseases and processes that are mediated by angiogenesis including, but not limited to, hemangioma, solid tumors, blood borne tumors, leukemia, metastasis, telangiectasia, psoriasis, scleroderma, pyogenic granuloma, myocardial angiogenesis, Crohn""s disease, plaque neovascularization, arteriovenous malformations, corneal diseases, rubeosis, neovascular glaucoma, diabetic retinopathy, retrolental fibroplasia, arthritis, diabetic neovascularization, macular degeneration, wound healing, peptic ulcer, Helicobacter related diseases, fractures, keloids, vasculogenesis, hematopoiesis, ovulation, menstruation, placentation, and cat scratch fever.
Another object of the present invention is to provide anti-growth factor antibodies useful for passively immunizing a human or animal against growth factor.
Yet another object of the present invention is to provide growth factor containing compositions that may be administered intramuscularly, intravenously, transdermally, orally, or subcutaneously.
These and other objects, features and advantages of the present invention will become apparent after a review of the following detailed description of the disclosed embodiment and the appended claims.